.head{
    z-index: 100;
    position:relative;
    width: 100%;
    border-bottom: 1px solid #b9d1f3;
    height: 66px;
    background-color: black;
}
.head .log{
    padding: 16px 30px ;
}
.head .nav{
    width: 470px;
 /*    position: absolute;
    left: 50%;
   margin-left: -235px; */
}
.head li{
    list-style: none;
    float: left;line-height: 66px;
    margin:  0 20px; 
}
.head li a{
    color: white;
}

.head .active{
     border-bottom: 2px solid white;
}
.head .dl{
    line-height: 66px;
  
}
.head .dl a{
    border:1px solid #b9d1f3;
    border-radius: 15px;
    padding: 8px 15px;
    color: white;
}

.head .dl .zc{
    margin: 0 30px 0 10px;
    border: none;}

/* 广告 */
.help{
    height: 290px;
    background-color: black;
}
.help-text{
    height: 290px;
    text-align: center;
    color: #fff;   
}
.help-text h2{
    font-size: 34px;
    padding-top: 84px;
    padding-bottom: 20px;
}
.help-text p{
    font-size: 14px;
    padding-bottom: 16px;
}
/* 案例 */
.case h3{
    font-size: 16px;
   color: black;
    font-weight: bold;
    padding-right: 10px;
    margin-top: 35px;
    margin-bottom: 25px;
}
.case h3 span{
     color: #99a5c1;
}
.case li{
    width: 350px;
   /*  height: 340px; */
    border: 1px solid #eeeeee;
}
.case li img{
    width: 330px;
    height: 140px;
    padding: 10px;
}
.case li h4{
    font-size: 16px;
    font-weight: bold;
    margin-top: 20px; 
    padding-left: 20px;
    padding-bottom: 14px;
}
.case li p{
    font-size: 10px;
    line-height: 15px;
   padding:0 15px;
   box-sizing: border-box;
}
.case li a{
    display: block;
    color: #1271ef;
    padding-top :27px; ;
    margin-left :15px; ;
    padding-bottom: 25px;
}